Membranvalg

Membranvalg, or membrane valve, is a type of fluid-control valve in which a thin, compliant membrane serves as the primary active element that modulates flow within a channel. It is widely used in microfluidics and soft-lithography based devices, as well as in some chemical processing and biomedical equipment, where integrated, low-pressure actuation and compact form are advantageous.

Typically constructed from two or more bonded layers containing a fluid channel and a control channel separated by a flexible membrane. When pressure is applied to the control channel, the membrane deflects toward the fluid channel and seals the flow, while releasing pressure returns the membrane to open. Designs include normally closed and normally open variants, and can be configured as two-way, three-way, or more complex valves. The membrane is often made from elastomeric polymers such as polydimethylsiloxane (PDMS), but other materials are used.

Actuation is usually pneumatic, using external pumps or pressure controllers; hydraulic or electrostatic actuation is also described in some literature. Advantages include rapid response, low dead volume, easy batch fabrication via soft lithography, and seamless integration with microchannels. Limitations include dependence on external pressure sources, potential for membrane fatigue or sticking, and material compatibility constraints with certain solvents or temperatures.

Applications span lab-on-a-chip systems, automated assays, cell culture, and chemical synthesis, where compact, programmable flow control is required. Membranvalg exemplifies how compliant membranes enable integrated, scalable fluid control in compact devices.